Child resistant closure

ABSTRACT

A child-resistant unit does holder includes a blister pack having a plurality of protrusions formed in a sheet and a unit dose disposed in each of the protrusions. The pack is slidably received in a sleeve which covers the protrusions to prevent a unit dose being dispensed from the pack. A releasable detent mechanism prevents slidable removal of the pack from the sleeve, and at least one of the protrusions forms a detent of the detent mechanism.

[0001] This invention relates to child resistant closures primarily butnot exclusively for blister packs for medicaments.

[0002] Many medicaments are packaged in blister packs comprising aplurality of deformable protrusions formed in a flexible sheet. Unitdoses of medicament are received in the protrusions which are sealed bya frangible film. To remove a unit dose, the unit dose is pushed throughthe frangible film. The arrangement is very convenient and widely used.Unfortunately it is also easy for unsupervised children to poisonthemselves by removing the unit dosages and ingesting them.

[0003] The invention seeks to render this kind of product more childresistant.

[0004] In U.S. Pat. No. 5,878,887 a blister card is received in a trayhaving a slidable cover. The cover has a tab with a locking projectionthat engages a slot in the tray. The pack can be partially opened bysliding the cover until the projection is at the end of the slot, andthen flexing the tab upwardly to release the locking projection from theslot. This allows the cover to slide to an open position permittingaccess to the blister card.

[0005] In U.S. Pat. No. 5,473, 371 a blister pack is folded in two andlocked in the folded position by a locking member. To access the pack,the locking member is manually flexed to disengage a locking tab fromthe notches in the pack so that the locking member can be slidablydisengaged from the pack. The pack can then be unfolded to provideaccess to the unit doses.

[0006] Providing a blister pack with a cover or sleeve that can beslidably removed only after releasing a locking mechanism reduces therisk of a child removing a unit dose without supervision. However theproducts described in the above US patents are generally complex andthere is a need for a more reliable and robust childproof lockingmechanism which does not add unduly to the cost of a blister pack andwhich is of a less complex design.

[0007] According to one aspect of the present invention there isprovided a child-resistant unit dose holder comprising: a pack having aplurality of protrusions formed in a sheet, and a unit dose disposed ineach of the protrusions; a sleeve for slidably receiving the pack, thesleeve covering the protrusions to prevent a unit dose being dispensedfrom the pack; and a releasable detent mechanism preventing slidableremoval of the pack from the sleeve, at least one of the protrusionsforming a detent of the detent mechanism.

[0008] By using one or more of the protrusions as a detent of the detentmechanism, a less complex and more reliable detent mechanism isprovided.

[0009] According to another aspect of the present invention there isprovided a child-resistant unit dose holder comprising: a pack having aplurality of protrusions formed in a sheet, each of the protrusionscontaining a unit dose and being spaced inwardly from opposed edges ofthe sheet; a sleeve for slidably receiving the pack, the sleevecomprising a flexible planar member having a pair of opposed inwardlyextending flanges forming a slot for receiving the opposed edges of thestrip, and a releasable detent mechanism preventing slidable removal ofthe pack from the sleeve, the detent mechanism being released inresponse to flexing of the planar member in a predetermined direction.

[0010] By way of example only, several embodiments of the invention willbe described by reference to the accompanying figures of which:

[0011]FIG. 1 is a perspective view of a blister pack;

[0012]FIG. 2 is a diagrammatic sectional view of the blister pack;

[0013]FIG. 3 is a perspective view of a sleeve for slidably receivingthe blister pack;

[0014]FIG. 4 shows the sleeve with the blister pack inserted;

[0015]FIG. 5 is a diagrammatic transverse sectional view through theassembly of FIG. 4 taken on a line through the unit doses;

[0016]FIG. 6 is diagrammatic transverse sectional view through theassembly of FIG. 4 and taken on a line between the unit doses;

[0017]FIG. 7 diagrammatically illustrates the assembly of FIG. 4 in itsflexed configuration;

[0018]FIG. 8 is a diagrammatic illustration of a sleeve having a foldline;

[0019]FIG. 9 is a perspective view of one alternative embodiment of asleeve;

[0020]FIG. 10 illustrates diagrammatically a retaining mechanism formaintaining engagement between the sleeve and the blister pack;

[0021]FIG. 11 illustrates diagrammatically an alternative retainingmechanism; and

[0022]FIG. 12 is a diagrammatic illustration of another embodiment ofthe invention.

[0023] Referring to these drawings, a conventional blister pack (FIGS. 1& 2) comprises a flexible sheet 2 having a plurality of protrusions 3formed therein. Unit dose 4 of medicament is received in at least someprotrusions. Frangible film 5 extends over the sheet 2 sealing the unitdosage in the protrusions. Frangible film 5 may be heat sealed or gluedto the sheet 2. Unit dose 4 is removed by pressing the top of protrusion3 to rupture the frangible film 5 where it overlies the protrusion. Thisarrangement is conventional and indeed the invention is useful onconventional blister packs.

[0024] A flexible sleeve 15 (FIG. 3) is provided for use with such ablister pack. Sleeve 15 can be formed of a plastics material, but couldbe a card or a card faced with plastics material. It comprises a planarsheet 14 having pair of longitudinal flanges 11 extending inwardly fromopposed sides to define a slot for receiving the blister pack. Sheet 14is of slightly greater width than the sheet 2 of the blister pack sothat the blister pack can be slidingly received in the sleeve as shownin FIG. 4. An additional transverse flange 10 closes the sleeve 15 atone end. This increases the childproof properties of the assembly sinceit is only possible to slide the blister pack out from one end of thesleeve.

[0025] Once the blister pack is received in the sleeve, the flanges 11of the sleeve extend part way across the sheet 2 of the blister pack.Cut-outs 12 in the flanges 11 are dimensioned and positioned such thatears 13 formed between the cut-outs engage the protrusions 3 on one sideof the blister pack (FIG. 4). At best seen in FIG. 5, with the blisterpack received in sleeve 15, the planar sheet 14 of the sleeve covers thefrangible film 5 of the blister pack so that access to the unit doses 4is prevented.

[0026] Since the ears 13 between the cut-outs 12 engage the protrusions3 of the blister pack, relative sliding movement is prevented.Accordingly, dispensing of a unit dose 4 can only be achieved bycoordinating a combination of actions. By squeezing the opposedlongitudinal sides of the sleeve together as indicated by the arrows inFIG. 6, the sleeve and the blister pack adopt a folded or arcuateconfiguration as shown in FIG. 7 with the flanges 11 of the sleevedeflected away from the sheet 14 and from the protrusions 3 so that theblister pack can be slid at least partially out of the sleeve to allowaccess to the medicament. Upon removal of the unit dose, the blisterpack may be returned back into the sleeve by repeating the aboveprocedure. A C-shaped portion of the planar sheet 14 can be removed atthe open end of the sleeve 15 to allow the user to grip the blister packand slide it out of the sleeve.

[0027] The planar sheet 14 of the sleeve may also comprise a fold line16 that runs parallel to the longitudinal sides of the sleeve as shownin FIG. 8. This would bias the sheet 14 against bending in the requireddirection shown in FIG. 7, thus improving the child resistant propertiesof the design. Only by inducing the sheet 14 to bend in the correctdirection against the fold line whilst squeezing the two sides of thesheet together would the flanges 11 be deflected away from theprotrusions 3. One or more fold lines may be present within the sheet14. Sliding need not be broadly parallel to the longitudinal axis of thepack as is shown in the figures since it may be possible to arrange foran angular or a zig-zag movement. One can envisage such co-ordinatedactions would be difficult for a child to perform.

[0028] One of the ways in which children gain access to medicamentcontained in conventional blister packs is by twisting them. Thisruptures the frangible layer, potentially allowing access to severalunit doses. The present sleeve 15 reduces the likelihood of thishappening as the sleeve adds rigidity to the whole structure.Furthermore if there is rupture while the pack is in the sleeve themedicament will be retained.

[0029] Modifications will be apparent to the skilled person. One or moreears may be provided on one or both of the flanges 11. In thealternative embodiment of FIG. 9, the opposed flanges 11 of the sleeveare joined by spaced apart parallel cross bars 17 disposed betweenadjacent pairs of the unit doses 4. With this arrangement the cross bars17 are raised into an arcuate configuration permitting passage of theunit doses 4 beneath them when the opposed longitudinal sides of thesleeve are gently squeezed together. The planar member 14 is curveddownwardly in the opposite direction. The cross bars may have variousshapes, such as a zig-zag shape, to accommodate different patterns ofthe protrusions on the blister pack.

[0030] One or more of the cross bars 17 may be physically attached tothe blister pack to prevent sliding movement even when the pack isflexed. In this case the attached bars would have to be torn orotherwise severed before flexing the pack to raise the remaining barsand permit slidable withdrawal of the pack from the sleeve.

[0031] A tie wrap (not illustrated) could also be used to prevent allsliding movement, the tie wrap passing around the sleeve eitherlongitudinally or transversely and being removed prior to flexing thesleeve to access the pack. Part of the tie wrap may be attached to thesleeve or to the blister pack so that it has to be detached before beingremoved.

[0032] The sleeve may be transparent. Where transparent the sleeve isparticularly useful for use with conventional blister packs where thename and dosage information is printed on the frangible film and will bevisible through the sleeve. Portions, especially non-transparentportions, of the sleeve can be provided with indicia. These indicia maycomprise patient information of the kind commonly provided on a leafletincluded with packaging which is liable to be mislaid.

[0033] Further modifications will be apparent to the skilled person. Forexample the cut-outs and ears could locate on protrusions not containingunit dose. Frangible sheet is not essential: the unit dose could bereceived in open mouthed cups sealed by the sleeve.

[0034] Additional means preventing separation of the blister pack fromthe sleeve 15 when the sleeve is flexed into or beyond the configurationshown in FIG. 7 may be provided. The skilled person will have nodifficulty in devising a suitable retaining mechanism. Examples includedetents such as a male portion 18, which may be moulded, of either thepack or the sleeve engaging a female portion 19 of the other of thesleeve and pack, (FIG. 10). The female portion may also be moulded. Inanother arrangement a T shaped male portion 20 of the sleeve may bereceived in a groove of the pack, (FIG. 11). In each case the retainingmechanism will allow relative sliding movement between the pack and thesleeve, but will prevent the pack being separated from the sleeve whenthe sleeve is flexed to the configuration of FIG. 7 or beyond.

[0035] A further modification is shown in FIG. 12. In this embodimentthe sleeve is of greater length than the pack. A first portion is asdescribed hereinbefore. A second portion 21 can be provided with a slotinto which the pack can be received. One or more but generally a smallnumber such as two holes 22 are provided in the second portion of thesleeve such that medicament can be dispensed. The first and secondportions can be joined by a fold line allowing the assembly to be foldedfor convenient storage. Medicament can then only be dispensed when unitdoses overlie the holes in the second portion. This limits the number ofunit doses which can be dispensed at one time and then only when thecorrect alignment has been achieved. This design also provides a largersurface for printing of patient information.

[0036] Any of the above features may be used in combination to improvethe child resistance or to ensure that only one combination ofoperations allows the blister pack to be indexed one position, afterwhich another or repeat combination of operations is required to indexit further.

1. A child-resistant unit dose holder comprising: a pack having aplurality of protrusions formed in a sheet and a unit dose disposed ineach of the protrusions, a sleeve for slidably receiving the pack, thesleeve covering the protrusions to prevent a unit dose being dispensedfrom the pack, and a releasable detent mechanism preventing slidableremoval of the pack from the sleeve, at least one of the protrusionsforming a detent of the detent mechanism.
 2. A child-resistant unit doseholder comprising: a pack having a plurality of protrusions formed in asheet, each of the protrusions containing a unit dose and being spacedinwardly from opposed edges of the sheet, a sleeve for slidablyreceiving the pack, the sleeve comprising a flexible planar memberhaving a pair of opposed inwardly extending flanges forming a slot forreceiving the opposed edges of the strip, and a releasable detentmechanism preventing slidable removal of the pack from the sleeve, thedetent mechanism being released in response to flexing of the planarmember in a predetermined direction.
 3. A unit dose holder according toclaim 2 in which the said flexing of the planar member in apredetermined direction deflects the flanges defining the slot away fromthe planar member.
 4. A unit dose holder according to claim 2 or claim 3wherein the detent mechanism includes a cross member extending betweenthe opposed flanges of the sleeve, the cross member normally engaging atleast one of the protrusions to prevent slidable removal of the packfrom the sleeve but being displaced out of the path of the protrusion inresponse to the said flexing of the planar member in the predetermineddirection.
 5. A unit dose holder according to claim 4 wherein theflexing of the planar member deforms the cross member into an arcuateconfiguration permitting passage of the protrusions beneath the crossmember and thereby permitting slidable removal of the pack from thesleeve.
 6. A unit dose holder according to claim 5 including a pluralityof the said cross members, each cross member being disposed between anadjacent pair of the protrusions.
 7. A unit dose holder according toclaim 6 in which one or more of the cross members is attached to thesaid sheet whereby the attached cross member(s) must be severed ordetached from the sheet before flexing the planar member to deform theremaining cross members into said arcuate configuration.
 8. A unit doseholder according to claim 2 wherein the pack is additionally retained inthe sleeve by a tie member wrapped around the sleeve, a portion of thetie being attached to the pack or to the sleeve, the said portion beingdetached prior to releasing the detent mechanism and removing the pack.9. A unit dose holder according to claim 2 wherein the detent mechanismis formed by the protrusions engaging at least one cut-out in at leastone of the opposed flanges defining the slot.
 10. A unit dose holderaccording to claim 2 further comprising means biasing the planar memberagainst flexing in the said predetermined direction.
 11. A unit doseholder according to claim 10 in which the biasing means comprises atleast one fold line extending parallel to the said opposed flanges ofthe planar member.
 12. A unit dose holder according to claim 2 furthercomprising a retaining mechanism permitting sliding movement between thepack and the sleeve while maintaining engagement between the pack andthe sleeve when the planar member is flexed in the said predetermineddirection.
 13. A unit dose holder according to claim 2 wherein the packis a blister pack, the unit doses being sealed in the protrusions by afrangible film, the planar member of the sleeve covering the flangiblefilm when the blister pack is disposed within the sleeve to prevent aunit dose being dispensed through the film.
 14. A unit dose holderaccording to claim 2 wherein the sleeve is of greater length than thepack, the arrangement being such that the portion of the sleeveextending beyond the pack is adapted to receive the pack when the detentmechanism is released and the pack is slidably removed from the portionof the sleeve originally holding the pack.
 15. A unit dose holderaccording to claim 14 in which the extended portion of the sleeveincludes at least one opening so arranged that a unit dose is dispensedonly when the opening is aligned with one of the said protrusionscontaining a dose.